I hear you about ventriloquists having mostly male dummies, but they are only one dummy per lap, reflecting the sex of the ventriloquist -- not an entire cast of characters. Bugs Bunny and the other Warner Bros. cartoon characters you mentioned, the Stooges, Laurel and Hardy, Abbot and Costello, and Martin and Lewis all had two things in common that the Muppets did not:
first, they were all strictly entertainment and not about children's education; and
second, they all pre-dated the movement for women's equality that directly coincided with the rise of the Muppets.
Most parents of children of the 80s and 90s were eager to teach both their male and female children that women were not just drag queen figures of fun and that males were not the only persons worth taking the lead role. Since the Muppets were promoted as primarily in the business of children's education, the sex balance mattered a great deal; yet it was decidedly off-kilter for the times then and the times now.
I could care less if Henson was gay or not gay. But for whatever reason, he did not present images of a balance of power, interest or inspiration between the sexes.
I see that you are gender obsessed regarding equality, and there is no point in any further discussion with you.
Have a nice life.